Some shared context and examples that I often use when dealing with CRUD actions in Rspec.

crud.rb

shared_examples :denied_access do
  before{ action }
  it { request.should redirect_to sign_in_path }
  it { response.status.should eq 302 }
end

shared_examples :response_ok do
  before{ action }
  it { response.should be_success }
  it { response.status.should eq 200 }
end

shared_examples :existing_resource do
  include_context :resource_class
  it "should expose the right resource" do
    action
    controller.send(resource_name).should eq resource
  end
end

shared_examples :found_and_redirected do
  before{ action }
  it { response.status.should eq 302 }
  it { response.should be_redirect }
  it "should redirect to right location" do
    if defined?(location)
      response.location.should match location
    end
  end
end

shared_examples :granted_access do
  it "should not redirect to the sign in path" do
    action
    response.should_not redirect_to sign_in_path
  end
end

shared_context :resource_class do
  before do
    @resource_class = resource_name.to_s.classify.constantize
  end
end

shared_examples :destroyed_resource do
  include_context :resource_class
  it "should destroy the resource" do
    action
    @resource_class.count.should eq 0
  end
end

shared_examples :created_resource do
  include_context :resource_class
  it "should create the resource" do
    expect{ action }.to change{@resource_class.count}.by(1)
  end
end

shared_examples :not_created_resource do
  include_context :resource_class
  it "should not create the resource" do
    previous_count = @resource_class.count
    action
    @resource_class.count.should eq previous_count
  end
end

shared_examples :malformatted_params do
  it "should raise an error" do
    expect{ action }.to raise_error(ActionController::ParameterMissing)
  end
end

shared_examples :new_resource do
  include_context :resource_class
  before{ action }
  describe "exposed resource" do
    subject{ controller.send(@resource_class.to_s.underscore) }
    its(:new_record?) { should be_true }
    its(:persisted?) { should be_false }
    it { should be_a @resource_class }
  end
end

shared_examples :not_updated_resource do
  include_context :resource_class
  it "should change the values" do
    action
    atrs.each do |key, value|
      resource.reload.send(key).to_s.should_not eq value.to_s
    end
  end
end

shared_examples :updated_resource do
  include_context :resource_class
  it "should change the values" do
    action
    atrs.each do |key, value|
      resource.reload.send(key).to_s.should eq value.to_s
    end
  end
end